The year 2021 marks the 150th anniversary of the publication of Charles Darwin's
extraordinary book The Descent of Man and Selection in Relation to Sex. Here, we review …

Highlights•The diverse 'other'social insects represent at least four social-evolutionary
paths.•The terminology for these societies is inaccurate and inconsistently applied.•New …

Many animals improve offspring survival through parental care. Research on coevolution
between parents has provided key insight into the genesis and maintenance of biparental …

The origin of parental care is a central question in evolutionary biology, and understating the
evolution of this behaviour requires quantifying benefits and costs. To address this subject …

Highlights•The idea of sex roles represents a stereotypical view of females and
males.•Researchers' perceptions of sex differences in nature are diverse.•Agreement with …

In males, large testes size signifies high sperm production and is commonly linked to
heightened sperm competition levels. It may also evolve as a response to an elevated risk of …

Harvestmen are a major arachnid order that has experienced a dramatic increase in
biological knowledge in the 21st century. The publication of the book Harvestmen: The …

In most animals, competition for mating opportunities is higher among males, whereas
females are more likely to provide parental care. In few species, though, these" …

Egg attendance imposes costs on parents, including decreased food intake and increased
mortality risks. By concentrating parental activities when egg predation is greater and abiotic …

Systematic infanticide of unrelated young has been reported in several animal taxa.
Particular attention has been given to carnivores and primates, where infanticide is a …